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How to convert a string to integer in C?
...u have it (but remember it's not portable):
long long
strtonum(const char *nptr, long long minval, long long maxval,
const char **errstr);
EDIT
You might also be interested in strtoumax and strtoimax which are standard functions in C99. For example you could say:
uintmax_t num = strto...
Converting string to byte array in C#
...[] GetBytes(string str)
{
byte[] bytes = new byte[str.Length * sizeof(char)];
System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
return bytes;
}
static string GetString(byte[] bytes)
{
char[] chars = new char[bytes.Length / sizeof(char)];
System.Buffer.B...
Best practices/performance: mixing StringBuilder.append with String.concat
...end(sN).toString();
concat()
String s = s1.concat(s2);
String creates char[] array that can fit both s1 and s2. Copies s1 and s2 contents to this new array. Actually requires less work then + operator.
StringBuilder.append()
Maintains an internal char[] array that grows when needed. No extra ...
C/C++中的段错误（Segmentation fault） - C/C++ - 清泛网 - 专注C/C++及内核技术
...ce
例子2：
Code:
#include <stdio.h>
int main(){
char *p;
p = NULL;
*p = 'x';
printf("%c", *p);
return 0;
}
很容易发现，这个例子也是试图往内存地址0处写东西。
这里我们通过gdb来查看段错误所在的行
...
What are the advantages of using nullptr?
... be an advantage. But consider the following overloaded functions:
void f(char const *ptr);
void f(int v);
f(NULL); //which function will be called?
Which function will be called? Of course, the intention here is to call f(char const *), but in reality f(int) will be called! That is a big probl...
What is the JavaScript equivalent of var_dump or print_r in PHP? [duplicate]
...ple 1: var_dump(1);
// returns 1: 'int(1)'
var output = '',
pad_char = ' ',
pad_val = 4,
lgth = 0,
i = 0;
var _getFuncName = function(fn) {
var name = (/\W*function\s+([\w\$]+)\s*\(/)
.exec(fn);
if (!name) {
return '(Anonymous)';
}
return name[1]...
best practice to generate random token for forgot password
...es DATETIME,
PRIMARY KEY(id)
);
... you need to add one more column, selector, like so:
CREATE TABLE account_recovery (
id INTEGER(11) UNSIGNED NOT NULL AUTO_INCREMENT
userid INTEGER(11) UNSIGNED NOT NULL,
selector CHAR(16),
token CHAR(64),
expires DATETIME,
PRIMARY K...
Explain the use of a bit vector for determining if all characters are unique
...
@Ivan Man, I was thinking the same thing. Even the selected answer didn't explain about the operators. Thank you for the detailed info.
– WowBow
Jan 6 '15 at 20:11
...
How to convert std::string to LPCSTR?
...
str.c_str() gives you a const char *, which is an LPCSTR (Long Pointer to Constant STRing) -- means that it's a pointer to a 0 terminated string of characters. W means wide string (composed of wchar_t instead of char).
...
Efficient Algorithm for Bit Reversal (from MSB->LSB to LSB->MSB) in C
... Bit Twiddling Hacks page:
Fastest (lookup table):
static const unsigned char BitReverseTable256[] =
{
0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF...